No. 1-ranked Nadal defeated fellow Spaniard Daniel Gimeno-Traver in his first-round match on Tuesday night, his first in more than three weeks after losing the Australian Open final to Stanislaw Wawrinka.

Nadal was an overwhelming favorite in Australia to win his 14th Grand Slam title, but he picked up the back strain warming up and was never the same.

"When one comes back from an injury in a short period of time, you can always feel a need to be cautious," he said. "I felt it (the back) a bit. But I hope things continue to improve day by day. Little by little the back will be strong again. I'll get used to the competition and the back won't keep me from playing future tournaments."

The Spaniard's next test is on Thursday against countryman Albert Montanes.

"I had a problem from Australia," Nadal said. "I tried to work on it at home and I'm back playing again. At the beginning one is a bit afraid coming back from a problem. I've worked hard to try to come back."

Nadal was sidelined for much of the 2012 season with a left knee injury. He used the Latin American clay-court circuit as his testing ground for the knee early in 2013.

It went OK. He won the French and US Open.

He's at it again early in 2014 with his back, reminding some that Nadal's big swings and aggressive play may be taking a toll on his 27-year-old body.

Nadal said after Tuesday's match — his 800th — that he'd played better than he'd practiced.

"Of course there are aspects of the game I have to improve," he said. "It's been a long time since I've played on the surface (clay), so It's normal to return without the best feeling."